The present invention relates to a device for feeding fuel and combustion air to internal combustion engines wherein the amount of combustion air fed is increased to meet certain changes in engine speed of adjustment.
In modern motor vehicles, ignition and mixture-forming systems which have a common regulation and control of the individual ignition and mixture forming systems in the form of digital motor electronics, also known as digital motor management, are generally used. To form the mixture, either central injection is used, in which the fuel is injected at only one place and then distributed over the cylinders, or multi-point injection is used, in which a separate valve is provided for each cylinder. The ignition system includes an ignition-map-based control with dwell-angle map which can be supplemented by knock control. Distribution of the ignition voltage is effected in this case by a high voltage distributor or without a distributor.
The heart of such a combined ignition and mixture forming system is a control device which, by means of maps, processes the data supplied by sensors in such a manner that the control pulses are optimal for one or more injection valves and one or more ignition coils with reference to the operating condition of the motor at the time. In this connection, the injection time as well as the dwell angle and firing angle are calculated in the control device by means of a microcomputer. It comprises an internal clock, a data bus, a microprocessor (CPU), a read-only memory (ROM), and a random access memory (RAM). The computer is ordinarily connected via an analog-to-digital converter to the analog sensors and, via output stages, to actuators which, as setting members, receive the pulses from the control device.
In light motors with small piston displacement, it is customary, in order to increase the power, to attach an exhaust gas turbocharger or a Root's blower by a flange to the motor in order to improve the cylinder filling by precompression of the air drawn in. In such a case, a supercharger pressure valve must also be integrated in the control and regulating circuit. The frequently cited advantages of increase in power by using an exhaust gas turbocharger (low power/weight ratio, less tendency to knocking, etc.) have, on the other hand, the disadvantage of providing relatively slow response upon acceleration from low speeds of rotation (turbohole) and relatively low power efficiency of the engine at low speeds of rotation (low exhaust gas velocity). Therefore, a noticeable increase in power is possible generally only in the middle and upper speed ranges. Since higher speeds of rotation produce a more frequent change of gas in the cylinder, the consumption of turbo engines in actual practice is frequently just as great as, and generally even greater than, in the case of aspirating motors of larger displacement, having the same power. Furthermore, due to the dead time between the giving of gas, e.g. opening the throttle, and the response of the supercharger, on the one hand, as well as between the cutting off of the gas and the decelerating of the supercharger on the other hand, sensitive dosaging of the power is not possible. Due to this characteristic, the turbo engine always somewhat overshoots the desired point and relatively high consumption is present, due to the difficulty in metering the power, even when no peak power is demanded from the engine.
Due to the nevertheless undeniable advantages of turbo charging, it would therefore be advisable to charge the engine only when high power is desired. Furthermore, the reaction time of the charging system should be less than is customary up to now. However, from the standpoint of construction, connecting or disconnecting is possible in the case of conventional supercharger designs only at unreasonably high expense.